Electronic systems typically include printed circuit board (PCB) assemblies having assortments of electronic components (e.g., high speed processors, memory devices, interface modules, etc.). Electronic components emit electromagnetic waves, also referred to as electromagnetic interference (EMI). If this EMI is not kept to acceptable levels (e.g., as defined by various agencies such as FCC in the USA and organizations responsible for control of RF spectrum in other countries) the PCB assemblies may cause malfunctions within the systems and to other systems in the vicinity. For example, an EMI interference produced by a PCB assembly may corrupt data handled by an adjacent PCB assembly within the same electronic system thus causing the overall operation of that system to fail. Furthermore, if the manufacturer of the electronic system cannot equip the system so that it passes required Radio-Frequency emissions testing, the electronic system is not permitted for sale.
A conventional scanning apparatus is available which helps circuit board manufacturers examine the EMI characteristics of a circuit board assembly. This apparatus includes (i) a rectangular plate which contains an array of probes, and (ii) multiple processors which are configured to scan for EMI emissions using the array of probes. The array of probes includes a high number of magnetic field pickup probes arranged in a grid with each probe being controlled through a complex switching scheme by a dedicated processor. The probes of the array are calibrated for precise EMI scanning within a very limited frequency range.
During operation, a technician connects the rectangular plate containing the array of probes to the processing devices. The technician then places the rectangular plate adjacent the circuit board assembly under test, and directs the processing devices to scan for EMI emissions from the circuit board assembly using the array of probes. If the technician subsequently wishes to scan for EMI emissions in a different frequency range, the technician replaces the initial rectangular plate containing the array of probes with a new rectangular plate having a different array of probes which is calibrated for operation at the different frequency range.